System for preventing contaminants from reaching a gas purifier

Abstract

The present invention is directed to the prevention of an exothermic reaction in the gas purifier of an ultra-high purity gas system.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application Ser. No. 60 / 986,754, filed on Nov. 9, 2007, which is incorporated herein by reference.FIELD OF THE INVENTION[0002]This invention relates to an ultra-high purity gas production plant. In particular, the invention is directed to the prevention of gas streams containing excessive contaminant levels from reaching and entering a gas purifier, thereby preventing an exothermic reaction from taking place in the purifier. Further, the novel system of the present invention eliminates the need to shut down the gas purifier or alternatively take it off-line.BACKGROUND OF THE INVENTION[0003]The manufacture of electronic components, such as semiconductor wafers, liquid crystal displays, light emitting diodes and solar cells typically requires nitrogen containing ten parts per billion (ppb) or less of several contaminants, including carbon monoxide, hydrogen, and oxygen. Nitrogen containing contaminants a...

AI Technical Summary

Benefits of technology

[0016]The oxygen level in conventional purity nitrogen leaving the air separation system is measured using an oxygen analyzer. The conventional purity nitrogen stream exiting the air separation system then enters a buffer volume that is upstream of the backup nitrogen tie-in point. This buffer volume is designed to delay the nitrogen from entering the purifier long enough for the oxygen analyzer to detect an excessive oxygen level, should one exist. If an excessive oxygen level is detected, the contaminated conventional purity nitrogen stream is isolated within the buffer volume and prevented from reaching the backup nitrogen tie-in point. Simultaneously, backup nitrogen flow is initiated to the gas purifier. As a result, the conventional purity nitrogen stream containing an elevated oxygen level does not reach the gas purifier and ultra-high purity nitrogen flow from the gas purifier to the end user is uninterrupted. The buffer volume is then back-purged with gas from the back-up source to extricate the contaminated gas. The air separation system stays isolated, i.e., conventional purity nitrogen from the air separation unit is vented and not redirected to the purifier until the source of the elevated contamination is determined.

Problems solved by technology

As a result, the conventional purity nitrogen stream containing an elevated oxygen level does not reach the gas purifier and ultra-high purity nitrogen flow from the gas purifier to the end user is uninterrupted.

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